Liquid mixing and distributing apparatus

ABSTRACT

In liquid mixing and distributing apparatus a unitarily formed tank provides a first compartment for receiving a primary liquid and a second compartment for receiving a secondary liquid. Float means in the first compartment serves to control the introduction and release of primary liquid into the first compartment. The same means also interconnects with a piston which is positioned to be immersible in the secondary liquid. By this interconnection, rise of liquid in the first compartment lowers the piston into the second compartment causing a metered portion of its liquid content to overflow into the first compartment, where admixture of the two liquids occurs. Adjustable blocking means are provided for limiting the degree of immersion of the piston and thus varying the quantity of secondary liquid which is displaced into the first compartment.

United States Patent MacPhee et a1.

July 8, 1975 LIQUID MIXING AND DISTRIBUTING APPARATUS Inventors: JohnMacPhee, Rowayton; Harold W. Gegenheimer, Darien, both of Conn.

[73] Assignee: BaldwimGegenheimer Corporation,

Stamford, Conn.

[22] Filed: May 20, 1974 [2]] Appl. No.: 471,208

[52] U.S. C1 137/10l.27; 137/l01.3l [51] Int. Cl. G05d 11/13 [58] Fieldof Search..... l37/10l.21, 101.25, 101.27, 137/1013] [56] ReferencesCited UNITED STATES PATENTS 395,651 1/1889 Blessing 137/1013] 3,358,70412/1967 Wyatt et a1. .1 137/1012] Primary Examiner-Robert G. NilsonAttorney, Agent, or FirmSt. Onge Mayers Steward & Reens [57] ABSTRACT Inliquid mixing and distributing apparatus a unitarily formed tankprovides a first compartment for receiving a primary liquid and a secondcompartment for receiving a secondary liquid. Float means in the firstcompartment serves to control the introduction and release of primaryliquid into the first compartment. The same means also interconnectswith a piston which is positioned to be immersible in the secondaryliquid. By this interconnection, rise of liquid in the first compartmentlowers the piston into the second compartment causing a metered portionof its liquid content to overflow into the first compartment, whereadmixture of the two liquids occurs. Adjustable blocking means areprovided for limiting the degree of immersion of the piston and thusvarying the quantity of secondary liquid which is displaced into thefirst compartment.

10 Claims, 12 Drawing Figures PATENTEU JUL 8 975 SHEET WM w y dk 1LIQUID MIXING AND DISTRIBUTING APPARATUS The present invention relatesto a liquid mixing and distributing apparatus and more particularly toapparatus for producing a solution having a desired combination ofingredients and thereafter controllably supplying the solution to an enduse destination. One primary use for the invention is in the printingindustry.

BACKGROUND AND BRIEF DESCRIPTION OF INVENTION Offset printing pressesare generally provided with a reservoir (generally the "water fountainpan) which is filled with a water solution of gum arabic and a slightproportion of chromic or phosphoric acid. The dampening rollers of thepress apply this etch and gum" water solution to the non-printingportions of the printing plate on the plate cylinder of the press, thusinsuring that no ink from the inking rollers will be received on thedampened portions of the plate. The proportions of a particular etch andgum solution are dictated by a number of factors, including the type ofink used, the nature of the printed work, the color being printed, andthe type of paper to be printed.

It has proven impractical to prepare and store large quantities of etchand gum solution over extended periods of time because of various kindsof deterioration that can occur in the course of such storage. On theother hand, some conditions of press operation may require thatrelatively great quantities of solution be supplied in a continuous run.To accommodate both these considerations, apparatus has heretofore beenprovided which can, under automated control, provide a continuoussuccession of freshly mixed batches of solution, with the addedpossibility of varying the proportions of the mix from time to time asmay be required by different printing assignments. An early version ofsuch apparatus is disclosed, for example, in US. Pat. No. 3,166,095,issued Jan. 19, 1965, in the names of Harold W. Gegenheimer, Andrew N.Stad, and Philip E. Tobias, and hereby incorporated by reference.

A critical element of batch mixing apparatus of the kind referred to isthe means provided for measuring precisely and reliably the amount ofetch and gum concentrate to be added to a known guantity of water andfor conveniently changing that amount under the control of the operator.in US. Pat. No. 3,166,095, referred to above, this function isaccomplished by means of a metering tank which is intermittently filledto capacity with etch and gum concentrate, but from which only apredeterminable fraction of the stored quantity is withdrawn foradmixture with the water solution. In a later development ofBaldwin-Gegenheimer Corporation, the assignee of the present invention,a similar function is provided by a repetitively refilled opentoppedtank which is floatably supported in the water solution to which themetered concentrate is to be added. Above the open top of the tank thereis positioned a fixed piston" which can enter the tank if the tank ismoved in the upward direction. In operation of the apparatus, suchupward movement of the tank actually occurs as increasing amounts ofwater are fed into a water-receiving space which surrounds the meteringtank. The resulting entry of the piston into the tank displaces somepart of the concentrate and causes it to overflow into the circumambientwater solution.

By preadjustment of the vertical position of the piston the amount ofconcentrate released for mixture with the water as the water approachesits maximum permitted level can be predetermined with entirelyacceptable accuracy. When the water has in fact reached its maximumlevel, a batch solution of the desired constituancy will have beenproduced and will be available for feeding (i.e. under operator orautomatic control) to the press fountain pan (or alternatively to acentral reservoir from which destribution to a number of presses is tobe accomplished).

The success of batch mixing of the kind just described has been such asto lead to continuing expansion of its field of application and to ademand for solution mixing and distributing apparatus of lower cost andstill greater accuracy. The present invention is concerned with meetingthese requirements. The invention provides in a highly compact assembly(i) a metering storage compartment for the etch and gum (orcorresponding) concentrate and (ii) a compartment in which theconcentrate is mixed into the water solution. The first of thesecompartments has an overflow point above which flow of concentrate mayoccur from the concentrate-containing space into the water-containingspace. A liquid-supply system is provided in connection with theconcentrate storage space, which in the normal operation of theapparatus, will tend to maintain a fixed minimum level of concentrate inthe storage space. Extending downwardly into the concentrate storagespace is a movable piston, which, as it is moved in the downwarddirection so as to become progressively immersed in the concentrate,raises the level of the concentrate to the overflow point, thus causingit to pass into the water-containing mixing chamber. The quantity ofconcentrate which overflows depends upon the extent of permitteddownward motion of the piston. As will be further explained in thedetailed description of the invention, this factor is made adjustable bythe operator, so that different proportions of water and concentrate canbe obtained as required by varying conditions of operation of theprinting presses with which the mixing apparatus is to be connected.

The water with which the etch and gum concentrate is to be admixed issupplied to the mixing compartment under the control of a floatpositioned in this compartment. This float may also be connected withcontrol mechanisms which enable it to initiate in-flow of water into thecompartment whenever the water level reaches a predetermined minimum andto terminate in-flow when a predetermined maximum level is attained.Operative means interconnect the float with the displacement pistonpreviously described in connection with the concentrate storage chamber,and by this means the piston is caused to increase its immersion in theconcentrate as the water level rises and to be progressively withdrawnfrom the concentrate as the water level falls toward its permittedminimum. in this way, rising of the water level initiates the meteredintroduction of etch and gum concentrate into the mixing compartment.Moreover, as will further appear in subsequent description, thecollocation of principal operating parts as so far described produces ahighly compact and low cost assembly of the entire apparatus.

Other aspects and advantages of the invention will become apparent uponconsideration of the following description taken in connection with theaccompanying drawings. in the drawings:

FIG. 1 is a perspective view of the external aspects of one embodimentof the invention;

FIG. 2 is an enlarged plan view of the apparatus of FIG. 1 with part ofthe top structure cut away;

FIG. 3 is an irregular sectional view taken on line 33 of FIG. 2, butwith all elements of that Figure restored,

FIG. 4 is a partial section taken upon line 44 of FIG. 2;

FIG. 4A is an enlarged and segmented plan view of certain elements ofFIG. 4',

FIG. 5 is a section (with upper part deleted) taken upon line 5-5 ofFIG. 3;

FIG. 6 is a section taken upon line 6-6 of FIG. 3',

FIG. 7 is a schematic assembly of certain of the principal functionalparts shown in FIGS. I through 5;

FIG. 8 is an enlarged detail, in section and partially broken away, ofpart of the structure shown in the left hand portion of FIG. 4;

FIG. 9 is a section taken on line 9--9 of FIG. 8;

FIG. 9A is a section taken on line 9A-9A of FIG. 8; and

FIG. 10 is an irregular section taken upon line I010 of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. I there is shownin that Figure the external configuration of the principal parts of theinvention assembled in their normal working relationship. This assemblyhas as its base portion a casing or tank II) which is so formed as to bereadily selfsupported upon any level surface. In an embodiment of theinvention which is preferred because it leads to low cost both in termsof material and fabricating requirements, the tank 10 consists of aunitary (one-piece) molded enclosure of liquid and etch-resistantplastic material, for example, polyvinyl chloride. It is provided at itsupper edge with a surrounding outwardly directed lip I5 which, asappears in FIG. 4, may be slightly offset from the plane of the verticaltank wall to provide an inwardly directed ledge 17 for the support of acover plate 20.

Supported on cover plate 20 is an inverted container which, as will befurther explained at a later point, is adapted to provide storage forfrom one to several gallons of a concentrated etch and gum solution orother concentrated solution intended in the operation of the apparatusto be admixed with water or other appropriate diluent or solvent. Forpresent purposes it is sufficient to note that the container 30 asillustrated comprises a water-tight and air-tight assembly consisting ofa cylindrical sidewall 32 of plastic, an imperforate end wall 34, agenerally similar wall 36 at its opposite extremity and take-up means ortie rods 38 for maintaining the end walls in firm assembly with thecylindrical sidewall 32. In the inverted position in which it is shownthe container 30 has a downwardly directed outlet system 40 which willbe described in detail at a later point.

Also supported on the cover plate 20 are two remov able (but normallysecured) casings 44 and 46 which enclose electrical and mechanicalcontrol devices to be further described at a later point. A water supplypipe 48 is also operatively connected to and through the cover plate 20,as will further appear. Also shown in FIG. I is a control assembly 50which will be shown to have an important role in controlling heproportions of the liquid mix which it is the function of the assembly10 to produce. At the right hand extremity of the assembly there isshown a liquid outlet conduit 60, also to be further referred to at alater point.

Referring now to FIG. 3, in which many of the items so far describedwill be readily identified, it will be seen that the tank 10 as viewedin longitudinal section comprises a first relatively largeliquid-receiving compartment which occupies the greater portion of theright hand part of the tank structure and has wing portions 70aextending to the left end of the structure. It is the function of thiscompartment to receive a substantial quantity of primary liquid (e.g.water) which in the course of operation of the apparatus is to beadmixed with a secondary constituent such as an etch and gumconcentrate. To the left of this first compartment. but in proximity toit, there is provided a second, smaller compartment 75, the wallstructure of which is shown as being formed continuously with the wallstructure of the compartment 70. It is the function of this compartmentto receive from the reservoir 30 the secondary liquid or concentrate.This second liquid is introduced into the compartment from the reservoir30 by means of the outlet system 40, already referred to. The details ofthis outlet system are significant to the functioning of the presentinvention and will therefore be described in detail at a later point. Itis sufficient at this point, however, to say that the conduit system hasa primary outlet 252 through which down-flowing liquid from thereservoir 30 is introduced into the chamber 75. The combination of theinverted reservoir 30 and the outlet system 40 provides a liquid levelmaintaining system of the type sometimes referred to as a chickenfeeder". In such a system the balance between the partial vacuumexisting in the upper portion of the reservoir 30 and the weight of theliquid column seeking egress through the outlet 252 causes asubstantially constant level of liquid to be maintained in the chamber75 as indicated at 78.

As may be seen by joint consideration of FIGS. 2 and 3, the compartment75 is an open top basin having a bottom wall 75a formed withconsiderable spacing between it and the supporting foundation of thetotal tank assembly 10. On three sides of this basin its lateralbounding wall is connected to and merges into the bounding wall of thetank 70 by means of a horizontal bridging part 75b. As appears moreclearly in FIG. 5, narrow extensions 70a of the compartment 70 extendalong and in effect enclose the lateral walls of the compartment 75. Itwill be apparent that by virtue of this arrangement the compartment 75may be said to have an overflow point above which liquid 78 contained inthat compartment will overflow the bounding surface 75b and drop intothe larger mixing compartment 70. The significance of this arrangementand the means by which overflow from the compartment 75 into thecompartment 70 can be made to occur will be explained in due course.

Reference will now be had to the liquid supply means by which the liquidin the tank 70 may be maintained between a predetermined minimum leveland a predetermined maximum level. These means include as a principalfunctioning element a float 80 which is constituted of a body ofmaterial having a significantly lower specific gravity than water. Thisbody may comprise, for example, a rigid block of closed cell polyvinylchloride foam. On the upper surface of the block 80 there is provided astainless steel plate 82 which, among other things, serves as aweight-increasing element to enable the block to perform acounterbalancing function which will be described at a later point.

As is best shown in FIG. 6, there is attached to the plate 82 anupwardly extending U-shaped bracket 85 secured by bolts 83 which projectinto the float 80. This bracket has vertical legs 85a and a transversepart 85b joining these legs. At the central region of the transversepart there is a slot 850 extending at right angles to the axis of thetransverse part. (See FIG. 40)

Still referring primarily to FIG. 6 (taken with FIG. 4), there issupported well above the central region of the float block 80 and withinthe covermounted casing 44 a twoway toggle switch 88 having apower-connected contact 88a and two alternatively usable contacts 88band 88c which, as will later appear, are respectively connected throughseparate solenoid valve controls to ground. This switch is of theover-center toggle variety, with its active switching member 88dconnected through a spring linkage 88 to a movable actuating head 88f.An operative connection between the switch 88 and the float block 80 isprovided by means of a push rod 90 which at its upper end is attached tothe switch actuator 88f by a linkage assembly 91 coacting with a fixedmounting bracket 92. The rod 90 extends downwardly through the slot 850in the transverse bracket part 85b (FIG. 4) so that its lower endapproaches but does not contact the plate 82. Circular collars 93a and93b are attached to the intermediate region of the rod in such a way(e.g. by set-screws) that their relative positions can be adjusted orpreset by the operator of apparatus. With this arrangement of parts itwill be seen that as the float 80 moves upward (i.e. during a period inwhich water is being fed from a supply source into the tank 70) a pointwill be reached, as represented in FIG. 4, at which the transversebracket part 85b will engage the collar 93b and cause the push rod tomove the switch actuator 88f (FIG. 4) into its uppermost position. Thiisaction will snap the powerconnected switch element 88a into contact withswitch terminal 88c. As will be more fully explained in the descriptionof FIG. 7, this will simultaneously cut off the incoming supply of waterto the tank compartment 70 and will initiate an outflow of water fromthe bottom of the tank, thus lowering the water level in the tank.

Because, as previously indicated, the switch 88 is of an over-centervariety, the reduction in water level will not immediately effect thecondition switch. However, when the float 80 has dropped significantly(i.e. with decreasing water level) a point will be reached at which thetransverse bracket part 85b will contact the upper surface of the rodcollar 93a, thus drawing the rod in the downward direction. When thishappens, the switch 88 will be thrown into its alternate position withthe contacts 88a and 88b in engagement. Under these circumstances, aswill subsequently be explained in detail, the outflow of water from thecompartment 70 will be halted and the influx of a fresh supply of waterwill begin. This cycle will continue indefinitely unless interrupted bythe operator of the equipment. It will be understood that the maximumand minimum levels which the water is permitted to attain can bepredetermined in advance by up and down adjustment of the rodbornecollars 93a and 93b. In general, the maximum level selected will alwaysbe at some point significantly below the overflow point (75b in FIG. 4)of the secondary compartment and the minimum point will be at least highenough to prevent the float from grounding" on the floor of thecompartment.

Before recapitulating the operation of the apparatus as so fardescribed, reference may usefully be had to the right hand portion ofFIG. 3 which shows in some detail the means by which water is withdrawnfrom the compartment 70. This means comprises a lever arm I00 fulcrumedto the end wall of the apparatus casing as indicated at 102. The lowerend of the lever arm, which is spring biased to the right, carries afrustoconical, partially hollow cap or cover member I05. In the positionshown in FIG. 3, this cap engages a bulkhead fitting or gasket 107having a central opening which leads to an outlet conduit 60. When thelever arm is rotated clockwise about the fulcrum 102, the capnecessarily moves away from the fitting 107, thus permitting water to bedrawn from the tank compartment 70 into the conduit 60. To prevent thecap from becoming vacuum locked to the fitting I07, the latter isprovided at its upper edge with an opening by which the passage to theconduit 60 is vented into a vertical duct 112 extending above themaximum attainable level of the liquid within the compartment 70. Flowof liquid into and through the conduit 60 to an end-use station (e.g., apress fountain) may be effected either by gravity flow or by use of apump attached to the conduit.

The overall operation of the water level control system as so fardescribed may best be summarized by reference to FIG. 7, in which itemsidentified in the Figures previously discussed bear similar numerals. Inthe condition of the apparatus shown in FIG. 7, the water level in thecompartment 70 has reached its prescribed minimum and the float 80 is inthe lowest position which it can attain with the indicated position ofthe stop collar 930. In these circumstances, it may be assumed that theswitching element 88a has snapped over from the dotted line position inwhich it engages contact 88b to the full line position in which it isshown in FIG. 7. The result of this transition is that solenoid which inits energized position holds the lever 100 in the illustrated dottedline position will have been de-energized, with the consequence that theclosure cap 105 has moved into engagement with the fulkhead fitting 107(i.e., as shown in full line illustration), thus terminating flow ofwater to the outlet conduit 60. Concurrently, the solenoid valve 125,which is normally closed, is energized and moved to its open position,thus allowing water to enter the compartment 70 through the supplyconduit 48, one part of which (labelled 48a) extends into the lowerregion of the compartment. The resulting interflow again raises thewater level in compartment 70 and moves the float 80 in the upwarddirection, a process which continues until the switch element 88a snapsinto engagement with contact 88b. At this point, solenoid valve is againdeenergized and solenoid 120 is energized, thus starting a new cycle ofdrain-and-refill. This process will continue until the apparatus as awhole is de-energized by opening the main power switch 130. In comparingthe several Figures of the drawings it will be found that other Figures(particularly FIGS. 1 and 3) indicate the mechanical location of itemssuch as the solenoid 120, its solenoid valve 125, and the switch whichhave been mentioned for the first time in the description of FIG. 7.

Having now described completely the system of water level controlprovided in connection with the primary tank compartment 70, it is inorder next to describe the means by which this system also functions tocontrol the supply of measured quantities of etch and gum solution fromthe secondary tank compartment 75. Referring particularly to FIGS. 3 and6, it will be seen that each of the vertical float-attached bracketparts 85a is provided with a pair of spaced pivot pins 140 and 141. Eachof the upper ones of these pins has rotatably secured to it a lever arm145 which is further rotatably secured to and supported by a fixedfulcrum provided by a pin or bolt 147. Each of the bolts 147 is in turnheld in place by a vertical bracket 148 having a secure attachment tothe cover plate 20 of the assembly as indicated at 150. Each lever armextends some distance to the left of the fulcrum pin 147, being providednear its left extremity with an upwardly directed notch 155. As may bestbe seen by joint consideration of FIGS. 2 and 3, each of the notchesengages (from below) a horizontally extending support bar 160, thefunction of which will be detailed at a later point.

Referring once again to the combination of FIGS. 3 and 6, it will beseen that each of the brackets 850 has further attached to it a secondlever arm 165 pivotally mounted on one of the bolts 141. This lever armextends between the bracket 85a and the bracket 148, being pivotallyattached to the latter by a pin or bolt 170. As may be discerned fromthe sectional view of FIG. 4, the two identical lever arms 165 areconnected at their right hand extremities by a bridging piece l65b withwhich they jointly form a U-shaped assembly having its open end directedto the left in FIG. 3. The combination of the fixed vertical brackets148, the levering members 145 and 165, and the float-attached brackets85a provides at each of two opposed extremities of the float 80 apantograph arrangement the effect of which is to assure that the bracketparts 85a remain perpendicular to the floor of the tank compartment 70as the float moves up and down. This in turn maintains the majorsurfaces of the float parallel with the floor of the tank and preventsthe float from assuming an angular position which might cause it tofrictionally engage any of the tank wall surfaces. As a further resultof this arrangement, the horizontal or bridging part 8512 of thefloatattached bracket system necessarily exerts completely verticalthrust upon the collars 91a and 91b attached to the switch actuatingpush rod 90. It is, of course, true that the pantograph mounting justdescribed will cause the float 80 to move somewhat to the right as itrises from the low-level position which it occupies in FIG. 3 and tomove back to the left as it sinks again in subsequent phase of theequipment operation. However, by virtue of the elongated slot 85cprovided in the bracket part 85b (see FIG. 4A) this motion will notresult in serious deflection or binding of the push rod 90.

It is now in order to consider the means by which motion of the float 80is enabled to produce measured transfer of etch and gum concentrate (orother activating liquid) from the secondary tank compartment 75 to theprimary compartment 70. Referring to FIG. 4, there will be seensuspended over the right hand region of the compartment 75 adisplacement block or piston 200, indicated as being of generally squaretransverse section. The other relative dimensions of the block are shownin FIG. 2. The block extends over only a portion of the area of thecompartment 75, leaving adequate clearance for the liquid conduitassembly 40. It is constituted of an appropriate liquid resistantmaterial and in a preferred embodiment comprises high density polyvinylchloride having specific gravity of about 1.4. Because of the lattercharacteristic it will tend to sink in the liquid 78 contained in thecompartment unless it is supported by means other than its buoyancy inthe liquid. The supporting means actually employed comprises in thefirst instance the horizontal bar I60 (FIG. 2). to which the piston isattached by spaced eye-bolts 205. The openings in these bolts aredimensioned to permit the piston to swing freely on the bar 160.

The bar itself has two separate means of support. The first of thesecomprises the pair of notched lever arms to which reference has alreadybeen made. The second comprises another pair of lever arms 2l0 which, ascan be seen in FIG. 2, are joined in a U- shaped assembly by across-member 2l0b extending between them at their right handextremities. The assembly is provided with oppositely disposed fulcrumpoints by extensions of the bolts or pins 147 supported in downwardlyextending bracket arms 148. by virtue of this arrangement, downwardmovement of the crossmember 2101) will lift the piston-supportingextremities of the lever arms 210. These extremities, in turn, areprovided with upwardly directed notches 2100 which are formed to receivethe extremities of the support bar 160.

It is the function of the lever arm 210, coacting with additional meansnow to be described, to limit the possible downward motion of thedisplacement block or piston 200 without regard to the maximum upwardmotion of the float 80, and thus to permit controlled variation of thequantity of secondary liquid which the piston can cause to overflow thecompartment 75. This is to be accomplished without concurrently alteringthe total quantity of primary liquid supplied to compartment 70. Theseobjectives are achieved by providing operator-controlled means foradjusting the degree to which the left hand ends of the lever arms 210(as seen in FIG. 4) can be drawn down by the weight of the displacementblock 200. The particular means provided for this purpose comprises acircular blocking member 220 affixed to the lower end of a verticaladjusting rod 225. As best seen in FIG. 4, this blocking member engagesthe upper surface of the lever-connected crossbar 21Gb when thecross-bar reaches a certain level, that level being variable inaccordance with the degree of downward extension of the adjusting rod225. Upon such engagement of parts, downward motion of the displacementblock 220 necessarily ceases regardless of its degree of submersion inthe etch and gum solution 78. Assuming that a predetermined quantity ofsolution has been deposited in the compartment 75 before downward motionof the displacement block begins, it will be apparent that limitation ofdownward motion of the block automatically determines the fraction ofthis quantity which will be caused to overflow the boundary surface 75b,and thus effectively meters the amount of concentrate which can flowinto intermixing relationship with the liquid in compartment 70.

As further appears in FIG. 4, the adjustment rod 225 is supported fromthe tank cover plate 20 by a fitting 227, which is internally threadedto engage external threads provided on the adjustment rod. Near itsupper end the rod is provided with a knurled knob 228 by which it can bescrewed up and down in the fitting 227. A pointed 229, also attached tothe upper end of the rod, (although not rotatable with it) coacts with ascale 23], marked with appropriate fluid measurements (e.g. ounces pergallon), so that, after initial calibration of the system, the locationof the pointer will indicate how much liquid is to be expelled fromcompartment 75 during a single cycle of operation of the apparatus. Theamount can be increased at any time by turning the knob 288 to raise theblocking plate 220 to a degree indicated by the change of position ofthe pointer 229. Conversely, the amount can be reduced by effectingdownward motion of the blocking plate.

While the lever arms 210 and the blocking plate 220 conjointly fix thelimits of motion of the piston 200, it will now be shown that theoccurrence of such movement in the first instance depends primarily uponaction of the earlier described lever arms 145. In this connection, itmay be assumed, for example, that the apparatus at the end of a fillingand mixing cycle is in the condition in which it is shown in FIG. 4. Itwill be seen in this FIG. that the float 80 is at a high level,corresponding to attainment of the maximum desired level of the primaryfluid. Under these conditions, the lever arms 145 have disengaged thepiston support bar 160 as they are free to do because of the opennothces 155 by which engagement of the arms and the bar areaccomplished. The piston thus stands supported solely by the independentlever arms 210. Consider, however, that the next phase of operation ofthe apparatus involves draining all liquid from the compartment 70. Assuch drainage occurs the float 80 will fall and the left handextremities of the lever arms 145 will rise. At a certain point, thenotches 155 will re-engage the crossbar 160 and, if effect, take overfrom the lever arms 210. In the preferred mode of operation of thissystem, the piston will be lifted by the lever arms 145 (ie as actuatedby the falling float 80) until it nearly (but not quite) leaves thesurface of the liquid in the compartment 75. Complete withdrawal of thepiston from the liquid is undesirable because, if this were permitted,in any operation following such withdrawal the piston would be requiredto move an indefinite distance before beginning to raise the level ofliquid in the cham ber 75. This would reduce the maximum realizabledisplacement of liquid.

It will be understood from the description of the apparatus as given sofar that, with the exception of the fittings for the outlet conduit 60(FIG. 3) and the parts 100 through I05 which coact with the outlet, alloperating components of the apparatus are mounted on the tank coverplate 20. As previously indicated, the cover plate is supported by theperipheral ledge 17 formed inside the upper edge of the tank. However,it is further supported by a pair of U-shaped brackets 23 (FIGS. 3 and4) so arranged that the closed part of the U bears in each case upon thefloor of the tank compartment 70. By virtue of these arrangements thecombination of the two tank compartments 70 and 75 can be formed as aunitary structure of molded liquid resistant plastic material, forexample, polyvinyl chloride which has been vacuum formed from sheetstock. Also, the flat cover plate may be formed of the same material.Accordingly, the cost of these major parts of the apparatus assembly isadvantageously low. Moreover, the attachment of the various operatingparts of the equipment to the cover plate 20 is readily accomplishedwith minimum expenditure of manufacturing time that the equipment as awhole is far less expensive than devices heretofore available forproducing etch and gum solutions.

It will be understood that the reservoir 30 of secondary liquid (e.g.etch and gum concentrate) can be lifted as a whole from the cover plate20 and refilled with fresh material at appointed intervals. This isdesirable not only to permit refilling the reservoir when empty, butalso in order to avoid the deterioration of quality which tends to occurin these materials if they are left unused for excessive periods oftime. The outlet system 40 employed in connection with the reservoir 30is the separate invention of John G. St. John, being claimed by him inUS. application Ser. No. 476,894, filed June 6, 1974. It has specialadvantages in the present context which make description of its detailsappropriate. For purposes of such description reference may be had toFIGS. 8 through 10.

The outlet assembly 40 is removable as a whole from the end wall 36 ofthe reservoir 30 by means of a screw thread 241 formed at the upper endof the hollow cylinder 242 which forms the enclosure of the assembly.This thread engages a corresponding thread formed internally on amouth-forming sleeve 30b which is attached to the reservoir end wall 36and which extends downwardly through an appropriately sized openingformed in the tank cover 20. A gasket 2410 forms a tight seal betweenthe end of the sleeve 30b and an annular flange 242a secured to theouter surface of the cylinder 242. The threaded end of the cylinder 242encloses in tight-fitting engagement a second cylinder or sleeve 243which has an inwardly tapered or countersunk end surface 243a. This isadapted to receive an interfitting closure member or stopper 244 whichin turn is attached to an axially extending push rod 246. This rod is ofsuch length that when the reservoir 30 is put in place on the tank cover20 as shown in FIG. 8 the lower end of the rod will engage the floor ofthe tank compartment as indicated at 246a. In consequence, the stopper244 is pressed away from the tapered opening 243a and liquid is free toflow into and through the cylinder 242. On the other hand, when thereservoir is moved away from the tank assembly (for refilling orotherwise), a compression spring 249 appropriately located at the lowerend of rod immediately pulls the stopper into closed position, thuspermitting the reservoir to be lifted and turned into an uprightposition without loss of liquid. This feature is not new in itself andis not described as novel. However, at the lower end of the cylinder242, there are provided novel means for controlling the release ofliquid into the tank compartment 70. These means comprise a cylindricalblock 250 interfitted within the bore of the hollow cylinder 242. Thisblock has a central opening for the rod 246 and two additional circularopenings 250a and 250b. The first of these receives a tubulation 252which, in the illustrated orientation of the apparatus extendsdownwardly below the intended level of the liquid 78 in the compartmentand provides the principal outlet for liquid from the reservoir 30 intothe compartment 70. The opening 25Gb receives at its upper end a secondtubulation 254 which is crimped and closed at its upper extremity asindicated at 2540 and which has in the sidewall of the crimped region arelatively small circular orifice 255. Through the opening thusprovided, the liquid within the cylinder 242 is in communication withthe main body of fluid in tank compartment 75 not only through the lowerend of the opening but also through a small lateral orifice 256 which islocated with its center line at the intended equilibrium level of theliquid pool 78. The effect of this arrangement is, first of all, that aslong as a supply of liquid concentrate remains in the reservoir 30, thelevel of such liquid maintained in the receiving compartment 75 tends tostabilize at approximately the midpoint of the opening 256. That is tosay, as long as the liquid pool is at or above the stated level, the airinlet path provided to the container through the still exposed part ofthe opening 256 is too restricted (by water surface tension orotherwise) to permit air bubbles to enter the enclosure 242.Accordingly, no air reaches the upper region of the container 30, andthe partial vacuum maintained in that region prevents liquid from beingreleased into the compartment 75, either through the tubulation 252 orthrough the opening 256.

It will be understood, however, that once the displacement piston (FIG.4) has been lowered sufficiently to cause a significant amount of liquidconcentrate to overflow into the mixing compartment and has thereafterbeen re-elevated by the weighted float (i.e. upon the withdrawal ofsolution from the mixing compartment), the liquid remaining in thecompartment 75 will (in the absence of replacement) fall below itsoriginal level. Once this begins to occur, however, the opening 256 willbecome fully uncovered, and a stream of small air bubbles will pass fromthis opening and through the orifice 255 into the upper reaches of thecontainer 30. [n this way, the vacuum in the container will be broken,so that liquid may be released through the tubulation 252. This willcontinue until the liquid level in compartment 75 again reaches themidpoint of theopening 256, at which time air flow will cease and a newcondition of stabilization will exist.

The liquid control system just described provides special advantages inavoiding large scale surges of inrushing air and out-rushing liquid atany time. That is to say, the succession of small air bubbles whichdevelops in the restricted path formed by the openings 256 and 255,taken in connection with the restricted liquid flow which can occurthrough tubulation 252, precludes the severe glugging" effect oftenencountered in vacuum-controlled liquid feed systems. This in turnprevents the occurrence of perturbations or fluctuations in liquid levelin compartment 75 sufficiently violent to cause liquid concentrate toslop over the wall surface 75b (FIG. 4) and thus to produceunpredictable variations in the proportions of the solution formed incompartment 70. It is believed sufficient for operability in thisfashion that the openings 255 and 256 and the opening in tubulation 252be specified as relatively small in proportion to the cross-section ofthe main passage within the cylinder 242. In a particular case goodresults have been obtained with a construction in which the cylinder 242has an internal bore of about one inch, and the openings 252, 255 and256 measure one quarter inch, one quarter inch and three eighths inch,respectively.

While the invention has been described by reference to a specificembodiment, it will be understood that numerous variations may be madeby those skilled in the art without department from the invention. Forexample, for special purposes, the float 80 may be separated into twoindependently floating parts, one of which controls the off-on functionof the water supply and the other of which operates the lever arms and165. Coordination of these functions will, of course, be maintained bythe fact that the two float parts will move synchronously with therising and falling of the water level in the tank compartment 70. [t istherefore intended in the appended claims to cover all modificationswhich fall within the ture spirit and scope of the invention.

What is claimed is the following:

I. Liquid mixing and distributing apparatus compris- A. a firstcompartment for receiving a primary liquid and having a combinationtherewith l. first liquid supply means having an on condition in whichit can introduce primary liquid into the first compartment and an offcondition in which introduction of further primary liquid into the firstcompartment is precluded;

2. a float in the first compartment which rises and falls with the levelof primary liquid in that compartment;

3. a liquid supply control connected with said float and operative whenthe liquid in the first compartment falls to a predetermined minimumlevel to turn said first liquid supply means to its on condition andoperative when the liquid reaches a predetermined maximum level to turnthat supply means to its off condition; and

4. control means effective when the liquid level in the firstcompartment reaches its maximum level to cause the liquid in thatcompartment to flow into a use conduit and effective when the liquidlevel in the compartment reaches its minimum level to preclude furtherflow of such liquid into the use conduit, whereby under the joint actionof said control means and the said liquid supply control, the liquid insaid compartment will oscillate between its maximum and minimum levels;

B. A second compartment arranged in proximity to said first compartmentfor receiving a secondary liquid to be mixed in measured quantities withthe primary liquid, said second compartment 1. having a point abovewhich liquid contained in that compartment will overflow into the firstcompartment; and

2. being provided with secondary liquid supply means effective duringuse of the apparatus to maintain a constant minimum level of thesecondary liquid in the second compartment;

C. a piston extending downwardly into the second compartment, saidpiston being movable vertically between a relatively elevated positionin which it does not displace sufficient secondary liquid to cause suchliquid to rise above the overflow point of the second compartment and arelatively depressed position in which it does displace sufficientsecondary liquid to cause such liquid to rise above said overflow pointand to flow into intermixing relationship with the liquid contained inthe first compartment; and

D. means effective to move the piston towards its relatively elevatedposition as the liquid level in said first compartment falls andeffective to move the piston towards its relatively depressed positionas the liquid level in the first compartment rises.

2. Apparatus according to claim 1 in which the said piston moving meansincludes an operative connection between the said float in the firstcompartment and the said piston for lowering the piston as the floatrises and vice versa.

3. Apparatus according to claim 2 in which the operative connectionbetween the float and the piston comprises A. a lever articulated at oneend to the float and articulated at the other end to the piston; and

B. a fulcrum for the lever located between its ends at a point such thatdownward movement of the float raises the piston and upward movement ofthe float produces lowering of the piston.

4. Apparatus according to claim 2 which further includes adjustablemeans for limiting the downward motion of the piston without regard tothe maximum upward motion of the float, thereby to permit controlledvariation of the quantity of secondary liquid overflowing into theprimary liquid without concurrently altering the quantity of liquidsupplied to the first compartment.

5. Apparatus according to claim 4 in which the said adjustable meansincludes a centrally pivoted lever which at one end has a part operativeto interrupt the downward movement of the piston and which at the otherend coacts with operator controllable means for adjusting the leverposition thereby to vary the point of limitation of downward movement ofthe piston.

6. A solution mixing and distributing apparatus comprising A. a tankstructure including 1. a first compartment for receiving a primaryliquid,

2. a second compartment for receiving a secondary liquid to be admixedin measured quantities with the primary liquid, and

3. a wall portion separating the two compartments, said wall portionbeing impervious to liquid flow below a predetermined level, but abovethat level permitting flow of liquid from the second compartment to thefirst compartment;

B. first liquid supply means having an on condition in which it canintroduce primary liquid into the first compartment and an off conditionin which introduction of further primary liquid into the firstcompartment is precluded;

C. second liquid supply means effective during use of the apparatus tomaintain a constant minimum level of the secondary liquid in the secondcompartment;

D. a float in the first compartment which rises and falls with the levelof primary liquid in that compartment;

E. a liquid supply control connected with said float and operative whenthe liquid in the first compartment falls to a predetermined minimumlevel to turn said first liquid supply means to its on condition andoperative when that liquid reaches a predetermined maximum level to turnthat supply means to its off condition;

F. a piston dimensioned to interfit within the second compartment, saidpiston having 1. a first vertical position in which it is suspendedwholly or largely above the second compartment, and

2. a second vertical position in which it extends downwardly within thecompartment so as to cause a preselected volume of liquid containedwithin the second compartment to rise above the said predetermined levelin respect to said wall portion of the compartment and to flow into anadmixing relationship with the liquid contained in the firstcompartment; and

G. a linkage between the said float and the said piston effective tomove the piston toward its said first vertical position as the liquidlevel in said first compartment falls and effective to move the pistontowards its said second vertical position as the liquid level in thefirst compartment rises.

7. Apparatus according to claim 6 in which the first compartment and thesecond compartment are formed unitarily of a single homogeneousmaterial.

8. Apparatus according to claim 7 in which the homogeneous material is amolded liquid-resistant plastic.

9. Apparatus according to claim 6 in which A. The said piston occupiesonly a portion of the transverse area of the second compartment; and

B. the second liquid supply means comprises an inverted liquid containersuspended above the second compartment and having a downwardly directedoutlet conduit which extends into the second compartment 1. in atransverse region of the compartment which is not occupied by the saidpiston, and- 2. to a point below the surface level of secondary liquidwhich is normally to be maintained in the compartment.

10. Liquid mixing and distributing apparatus comprising A. a firstcompartment for receiving a primary liquid and having in combinationtherewith 1. first liquid supply means having an on condition in whichit can introduce primary liquid into the first compartment and an offcondition in which introduction of further primary liquid into the firstcompartment is precluded;

2. means responsive to changes in the level of primary liquid in thatcompartment;

3. a liquid supply control connected with said lastmentioned means andoperative when the liquid in the first compartment falls to apredetermined minimum level to turn said first liquid supply means toits on condition and operative when the liquid reaches a predeterminedmaximum level to turn that supply means to its off condition; and

4. control means effective when the liquid level in the firstcompartment reaches its maximum level to cause the liquid in thatcompartment to flow into a use conduit and effective when the liquidlevel in the compartment reaches its minimum level to preclude furtherflow of such liquid into the use conduit, whereby under the joint actionof said control means and the said liquid supply control, the liquid insaid compartment will oscillate between its maximum and minimum levels;

B. A second compartment arranged in proximity to said first compartmentfor receiving a secondary liquid to be mixed in measured quantities withthe primary liquid, said second compartment 1. having a point abovewhich liquid contained in that compartment will overflow into the firstcompartment; and

secondary liquid to cause such liquid to rise above said overflow pointand to flow into intermixing relationship with the liquid contained inthe first compartment; and

D. means effective to move the piston towards its relatively elevatedposition as the liquid level in said first compartment falls andeffective to move the piston towards its relatively depressed positionas the liquid level in the first compartment rises. =0 i

1. Liquid mixing and distributing apparatus comprising A. a firstcompartment for receiving a primary liquid and having a combinationtherewith
 1. first liquid supply means having an on condition in whichit can introduce primary liquid into the first compartment and an offcondition in which introduction of further primary liquid into the firstcompartment is precluded;
 2. a float in the first compartment whichrises and falls with the level of primary liquid in that compartment; 3.a liquid supply control connected with said float and operative when theliquid in the first compartment falls to a predetermined minimum levelto turn said first liquid supply means to its on condition and operativewhen the liquid reaches a predetermined maximum level to turn thatsupply means to its off condition; and
 4. control means effective whenthe liquid level in the first compartment reaches its maximum level tocause the liquid in that compartment to flow into a use conduit andeffective when the liquid level in the compartment reaches its minimumlevel to preclude further flow of such liquid into the use conduit,whereby under the joint action of said control means and the said liquidsupply control, the liquid in said compartment will oscillate betweenits maximum and minimum levels; B. A second compartment arranged inproximity to said first compartment for receiving a secondary liquid tobe mixed in measured quantities with the primary liquid, said secondcompartment
 1. having a point above which liquid contained in thatcompartment will overflow into the first compartment; and
 2. beingprovided with secondary liquid supply means effective during use of theapparatus to maintain a constant minimum level of the secondary liquidin the second compartment; C. a piston extending downwardly into thesecond compartment, said piston being movable vertically between arelatively elevated position in which it does not displace sufficientsecondary liquid to cause such liquid to rise above the overflow pointof the second compartment and a relatively depressed position in whichit does displace sufficient secondary liquid to cause such liquid torise above said overflow point and to flow into intermixing relationshipwith the liquid contained in the first compartment; and D. meanseffective to move the piston towards its relatively elevated position asthe liquid level in said first compartment falls and effective to movethe piston towards its relatively depressed position as the liquid levelin the first compartment rises.
 2. Apparatus according to claim 1 inwhich the said piston moving means includes an operative connectionbetween the said float in the first compartment and the said piston forlowering the piston as the float rises and vice versa.
 2. being providedwith secondary liquid supply means effective during use of the apparatusto maintain a constant minimum level of the secondary liquid in thesecond compartment; C. a piston extending downwardly into the secondcompartment, said piston being movable vertically between a relativelyelevated position in which it does not displace sufficient secondaryliquid to cause such liquid to rise above the overflow point of thesecond compartment and a relatively depressed position in which it doesdisplace sufficient secondary liquid to cause such liquid to rise abovesaid overflow point and to flow into intermixing relationship with theliquid contained in the first compartment; and D. means effective tomove the piston towards its relatively elevated position as the liquidlevel in said first compartment falls and effective to move the pistontowards its relatively depressed position as the liquid level in thefirst compartment rises.
 2. a float in the first compartment which risesand falls with the level of primary liquid in that compartment;
 2. beingprovided with secondary liquid supply means effective during use of theapparatus to maintain a constant minimum level of the secondary liquidin the second compartment; C. a piston extending downwardly into thesecond compartment, said piston being movable vertically between arelatively elevated position in which it does not displace sufficientsecondary liquid to cause such liquid to rise above the overflow pointof the second compartment and a relatively depressed position in whichit does displace sufficient secondary liquid to cause such liquid torise above said overflow point and to flow into intermixing relationshipwith the liquid contained in the first compartment; and D. meanseffective to move the piston towards its relatively elevated position asthe liquid level in said first compartment falls and effective to movethe piston towards its relatively depressed position as the liquid levelin the first compartment rises.
 2. means responsive to changes in thelevel of primary liquid in that compartment;
 2. to a point below thesurface level of secondary liquid which is normally to be maintained inthe compartment.
 2. a second vertical position in which it extendsdownwardly within the compartment so as to cause a preselected volume ofliquid contained within the second compartment to rise above the saidpredetermined level in respect to said wall portion of the compartmentand to flow into an admixing relationship with the liquid contained inthe first compartment; and G. a linkage between the said float and thesaid piston effective to move the piston toward its said first verticalposition as the liquid level in said first compartment falls andeffective to move the piston towards its said second vertical positionas the liquid level in the first compartment rises.
 2. a secondcompartment for receiving a secondary liquid to be admixed in measuredquantities with the primary liquid, and
 3. a wall portion separating thetwo compartments, said wall portion being impervious to liquid flowbelow a predetermined level, but above that level permitting flow ofliquid from the second compartment to the first compartment; B. firstliquid supply means having an on condition in which it can introduceprimary liquid into the first compartment and an off condition in whichintroduction of further primary liquid into the first compartment isprecluded; C. second liquid supply means effective during use of theapparatus to maintain a constant minimum level of the secondary liquidin the second compartment; D. a float in the first compartment whichrises and falls with the level of primary liquid in that compartment; E.a liquid supply control connected with said float and operative when theliquid in the first compartment falls to a predetermined minimum levelto turn said first liquid supply means to its on condition and operativewhen that liquid reaches a predetermined maximum level to turn thatsupply means to its off condition; F. a piston dimensioned to interfitwithin the second compartment, said piston having
 3. Apparatus accordingto claim 2 in which the operative connection between the float and thepiston comprises A. a lever articulated at one end to the float andarticulated at the other end to the piston; and B. a fulcrum for thelever located between its ends at a point such that downward movement ofthe float raises the piston and upward movement of the float produceslowering of the piston.
 3. a liquid supply control connected with saidlast-mentioned means and operative when the liquid in the firstcompartment falls to a predetermined minimum level to turn said firstliquid supply means to its on condition and operative when the liquidreaches a predetermined maximum level to turn that supply means to itsoff condition; and
 3. a liquid supply control connected with said floatand operative when the liquid in the first compartment falls to apredetermined minimum level to turn said first liquid supply means toits on condition and operative when the liquid reaches a predeterminedmaximum level to turn that supply means to its off condition; and 4.control means effective when the liquid level in the first compartmentreaches its maximum level to cause the liquid in that compartment toflow into a use conduit and effective when the liquid level in thecompartment reaches its minimum level to preclude further flow of suchliquid into the use conduit, whereby under the joint action of saidcontrol means and the said liquid supply control, the liquid in saidcompartment will oscillate between its maximum and minimum levels; B. Asecond compartment arranged in proximity to said first compartment forreceiving a secondary liquid to be mixed in measured quantities with theprimary liquid, said second compartment
 4. control means effective whenthe liquid level in the first compartment reaches its maximum level tocause the liquid in that compartment to flow into a use conduit andeffective when the liquid level in the compartment reaches its minimumlevel to preclude further flow of such liquid into the use conduit,whereby under the joint action of said control means and the said liquidsupply control, the liquid in said compartment will oscillate betweenits maximum and minimum levels; B. A second compartment arranged inproximity to said first compartment for receiving a secondary liquid tobe mixed in measured quantities with the primary liquid, said secondcompartment
 4. Apparatus according to claim 2 which further includesadjustable means for limiting the downward motion of the piston withoutregard to the maximum upward motion of the float, thereby to permitcontrolled variation of the quantity of secondary liquid overflowinginto the primary liquid without concurrently altering the quantity ofliquid supplied to the first compartment.
 5. Apparatus according toclaim 4 in which the said adjustable means includes a centrally pivotedlever which at one end has a part operative to interrupt the downwardmovement of the piston and which at the other end coacts with operatorcontrollable means for adjusting the lever position thereby to vary thepoint of limitation of downward movement of the piston.
 6. A solutionmixing and distributing apparatus comprising A. a tank structureincluding
 7. Apparatus according to claim 6 in which the firstcompartment and the second compartment are formed unitarily of a singlehomogeneous material.
 8. Apparatus according to claim 7 in which thehomogeneous material is a molded liquid-resistant plastic.
 9. Apparatusaccording to claim 6 in which A. The said piston occupies only a portionof the transverse area of the second compartment; and B. the secondliquid supply means comprises an inverted liquid container suspendedabove the second compartment and having a downwardly directed outletconduit which extends into the second compartment
 10. Liquid mixing anddistributing apparatus comprising A. a first compartment for receiving aprimary liquid and having in combination therewith